Built to compete against the Fiat G.49 and Macchi M.B.323 as a replacement for the North American T-6 used widely by the Aeronautics Militare Italians, the Piaggio P.150 made its first flight in November 1952. An all-metal cantilever low-wing monoplane with square cut wingtips and tailplane, the P.150 had wide-track inward-retracting main landing gear legs. Pupil and instructor were housed in tandem with dual controls, under a long glazed canopy. The original powerplant was a 447kW Pratt & Whitney Wasp R-1340-S3H1 radial engine, which gave a maximum speed of 380km/h. A later version was fitted with a geared Alvis Leonides engine, but the type was not considered suitable to be built in quantity for the Italian air arm.